Device for registering sheets on feed board of sheet fed printing machines

ABSTRACT

A sheet registering arrangement for positioning sheets on a feed board prior to take-off and transfer to a printing unit. Seated engagement of the leading edge of a sheet with front guide means is maintained during register with a side guide member in the form of a short length of fence by pivotally mounting the side guide member so that it is free to swivel into self-alignment with the lateral edge of the sheet. Thus, non-square sheets can be reproducibly registered. Light biasing of the side guide member by means of springs or the like can be used to place the member in a neutral position, when no sheet is present. The neutral position can be made adjustable so as to accommodate sheets with different characteristic angular errors.

United States Patent [1 1 Krochert 1 DEVICE FOR REGISTERING SHEETS ON FEED BOARD OF SHEET FED PRINTING MACHINES Karl-Heinz Krochert, Offenbach/Main, Germany Assignee: Roland Offsetmaschinenfabrik Faber & Schleicher AG Y [22] Filed: July 24, 1972 [211 Appl. No.: 274,609

Inventor:

[301 Foreign Application Priority Data July 28, 1971 Germany ..FZ1 37 661.4

[52] US. Cl. 271/58, 271/59 [51] Int. Cl B65h. 9/00, B65h 7/10 Field of Search 271/58, 59, 48, 49,

[ Aug. 28, 1973 Meltendorf 271 58 Peyrebrune 271/59 5 7 ABSTRACT A sheet registering arrangement for positioning sheets on a feed board'prior to take-off and transfer to a printing unit. Seated engagement of the leading edge of a sheet with front guide means is maintained during register with a side guide member in the form of a short length of fence by pivotally mounting the side guide member so that it is free to swivel into self-alignment with the lateral edge of the sheet. Thus, non-square sheets can be reproducibly registered. Light biasing of the side guide member by means of springs or the like can be used to place the member in a neutral position, when no sheet is present. The neutral position can be made adjustable so as to accommodate sheets with different characteristic angular errors.

5 Claims, 11 Drawing Figures Patented Aug. 28, 1973 2 Sheets-Sheet S DEVICE FOR REGISTERING SHEETS ON FEED BOARD OF SHEET FED PRINTING MACHINES This invention relates to improvements in sheet registering arrangements associated with a printing machine in which sheets are conveyed rapidly in succession to a feed board where front and side registery is effected, after which the sheets are individually taken and transferred to a printing unit. More particularly, the present invention relates to sheet registering arrangements useful with respect to non-square sheets which, after initial front guide registering, can be brought into register with a side guide without losing register with the front guides. v

With respect to high speed printing operations and particularly with multi-color printing, it is necessary to insure the each of the sheets successively brought into contact with the impression cylinder be reproducibly aligned. To accomplish this, it is customary to register the sheets on a feed board with front and side guides prior to their transfer to the printing machine.

Means for accomplishing sheet registering are disclosed in German Pat. No. 870,42l and in German Pat. publication No. 1,051,291 and involve first registering the leading edge of the sheet with front guides and thereafter moving the sheet laterally into register with a side guide which, in order to prevent buckling, is sufficiently long as to contact the sheet over a portion of the sheet edge and not simply at a point. However, when the sheet is not completely square, registration of the sheet with the side guide causes the sheet to be drawn out of register with the front guides or, perhaps,

' scription and upon reference to the drawings in which:

with both guides. As a result, the sheets will not be squarely and reproducibly transferred to the impression cylinder. 7

With respect to sheets which are not square but are nevertheless trimmed uniformly, it is possible to preset the position of the side guide with respect to the feed board before a printing run in order to compensate for the angle of trim. However, this imposes an additional responsibility on the printer. Furthermore, it is difficult to achieve truly uniform trimming and, as'a result, presetting of the side guide will at best be only marginally effective in assuring reproducible register of the sheet.

Accordingly, it is an object of the present invention to provide an improved sheet registering arrangement in which substantially exact register of sheets on a feed board is achieved irrespective of sheet squareness.

A further object is in providing an improved sheet registering arrangement which effectively registers all sheets encountered during a given production run without necessitating multiple adjustments of the registering guide means during the run.

An additional object resides in providing a registering arrangement having the attributes identified in the foregoing objects in which the side guide means is easily adjustable prior to a production run to accommodate a given batchof sheets with a substantially uniform trimming angle.

Yet a further object of the present invention is to provide a sheet registering arrangement wherein improved sheet register is achieved singularly through novel side guide means thereby permitting the use of customary sheet feeding and transfer mechanisms.

Thus, an additional object is in providing novel side guide means in which sheet register therewith can be achieved without buckling after register with front guide means and without sheet dislodgement there- FIG. I is a side elevation, partly diagrammatic, of the sheet registering device and adjacent portion of a printing unit.

FIG. 2 is a top view of the feed table looking along the line 2-2 of FIG. I" and showing the sheet profile.

FIG. 3 is a view in elevation of a side guide assembly looking along the line 3-3 in FIG. 1.

FIG. 5 is a top view of the side guide memb'er 'illustrated in FIG. 4.

FIG. 6 is a view similar to FIG. 4 showing an alternate pivoting means.

FIG. 7 is a fragmentary top view showing a guide member including light biasing spring for defining the neutral position.

FIG. 8 is a diagrammatic plan illustrating the dislodgement which may take place with conventional side guide members.

FIG. 9 shows successful registration of a sheet having angular error.

FIGS. 10 and 11 are fragmentary side and top views respectively of a modification which permits adjustment of neutral angle.

While the invention has been described in connection with certain embodiments, it will be understood that there is no intention to limit the invention to the particular embodiments shown but it is intended, on the contrary, to cover the various alternative and equivalent constructions included within the spirit and scope of the appended claims.

Turning now to FIGS. 1 and 2, there is shown a printing press 10 having an impression cylinder 11 cooperating with a printing cylinder 12, the two cylinders being driven in the conventional way by a.press drive 13. Sheets of paper to be printed by these cylinders are of nominally rectangular shape as shown at 15 in FIG. 2

having a leading edge 16 and a lateral edge 17. The sheets, fed one by one, are supported on a feed board 20 having a pair of front register members 21, 22 laterally spaced in alignment along the front edge of the board. It will be understood that the front guides and the means for mounting and operating the same may be conventional. For the purpose of transferring a sheet from the feed board to the impression cylinder II, a pregripper assembly 25 is provided which transfers the sheet to grippers on the impression-cylinder, which grippers are not, however, shown and will be understood to be conventional. It will also be understood that the means, indicated at 26, for releasing sheets one by one are conventional. The front guide means 21, pregripper 25 and the sheet release 26 are all actuated in synchronism with one another as taught in numerous patents in the prior art, the synchronizing means being generally indicated at 27.

In accordance with the present invention a side guide member is provided located at one side of the feed board for registering the side edge of the sheets, with the sheets being fed one by one onto the feed board along a path which clears the side guide member by a relatively small amount of clearance as the sheets move into seated engagement with the front guide means. Means are provided adjacent the side guide member and synchronized with the arrival of the sheet at the front guide means for urging the sheet laterally into engagement with the side guide member, the side guide member being in the form of a short length of fence" presenting a vertical sheet-engaging face which extends both upwardly and downwardly with respect to the surface of the feedboard, the side guide member being pivoted for rotation about a vertically extending pivot so that when a sheet is urged laterally into engagement with the guide member it is swiveled into self-alignment with the presented edge of the sheet. Thus, turning to FIGS. 4 and 5 a typical side guide member is shown in the form of a short length of fence" presenting a face 3] to the edge 17 of the sheet 15. The side guide member has a bracket or mounting portion 32 which swings about a vertically arranged bolt 33 providing a loose swivel type joint and which is screwed into a mount 34. The mount presents corners 35 for limiting the range of swiveling movement to a matter of a few degrees. The presented face 31, as will be noted, extends both above and below the surface of the table 20 so as to be sure to be in the path of movement of the edge 17 of the sheet. In a practical case the side guide member 31 may have a length on the order ofa few inches so that the alignment forces are not overly concentrated upon the edge and so that sufficient torque is developed, upon engagement, to bring about the selfaligning action.

For the purpose of urging the sheet 15 into engagement with the side guide member 30 a mechanism is provided as shown in FIG. 3.- Such mechanism includes a wiper arm 41 arranged under the sheet 15 and having an arcuate wiping surface 41, the arm being stationarily pivoted at 43. The wiper arm preferably extends up through a suitable slot or clearance space in the feedboard 20 to provide grazing action on the underside of the sheet for urging the sheet in the direction of the side guide member, i.e., to the right as shown in FIG. 3. For cooperating with the wiper arm 41 a backup roller 44 is provided on top of the sheet pivoted at 45, and mounted upon a bell crank 46 which is pivoted to a stationary frame structure at 47. For the purpose of biasing thebackup roller 44 downwardly a spring 48 is provided which bears against an upwardly extending arm 46a of the bell crank.

To lift the roller 44 clear of the feed board to clear an incoming sheet, and, again, to lift the roller at the time that the sheet is transferred, the bell crank 46 includes a downwardlyextending arm 46c which engages a box cam member 50 mounted upon a reciprocating rod 51.

Means are, moreover, provided for raising the side guide member 30 free of the feed board during the time that a sheet is being fed and removed and in synchronism with the vertical motions of the backup roller 44. Thus the bracket, or mount, 34 for the side guide is secured to a second bell crank 52 which is also rotatable about the pivot 47 and which is also biased for movement in the direction of the feed board, such bias being provided by a spring 53 which acts upon an arm 52a of the bell crank 52. The level of the bracket, or mount, 34 and hence the level of the side guide member 30, is determined by a stop 55 in the form of an adjusting screw 56 having a lock nut 57. I

Thus when the rod 51 and box cam element 50 move to the left the bell crank 46 is swung clockwise moving the backup roller 44 upwardly away from the feed board. Upon continued upward motion the bell crank 46 picks up the bell crank 52 so that the side guide member is also raised clear of the feed board.

In order to prevent the engaged sheet from buckling under the scuffing action of the wiper arm 41, a guard plate 58 is secured, as shown, to the underside of the bracket 34.

Turning attention again to the wiper arm 41, it is engaged by a second box cam member 60 mounted upon the shaft 51 and which works against a return spring 61.

While a simple form of swivel connection is shown in FIGS. 4 and 5, there is an alternate form disclosed in FIG. 6 in which corresponding parts are correspondingly numbered with addition of subscript a. In this embodiment the side guide member 30a is secured to the bracket 34a by means of a pivot pin 33a.

In the embodiments shown in FIGS. 4-6, except for the limit stops, the sheet alone determines the angle of orientation of the guide member. In one of the aspects of the presentinvention lightly biased means are provided for maintaining the side guide member centered at a neutral" or normal orientation at all times when the guide member is not engaged by the sheet, the neutral position approximating the position the guide member will occupy when fully engaged by the sheet. Thus, turning to FIG. 7, in which corresponding parts are indicated by corresponding numbers 'with addition of subscript b, the guide member 30b is mounted upon the bracket 34b by a pin 33b to provide free swiveling action. The neutral" position of the guide member is determined by light biasing springs 71, 72 which provide opposing torques. This insures that the guide member will be maintained in an orientation which closely matches the edge of the sheet so that any angling error in the edge of the sheet will be immediately accommodated by only slight swiveling movement of the guide member, against the light centering force of the springs, so that the guide member achieves prefect self-alignment with maximum angular movement.

As a still further refinement of the construction means may be provided for varying the neutral position of a spring-centered guide member as shown in FIGS. 10 and 11, where corresponding elements are indicated by corresponding numerals with addition of subscript c. Here the guide member 30c is mounted upon bracket 340 by means ofa vertical pivot pin 33c. Mounted upon the guide member so as to form a rigid extension of it is an arm to which is attached a coil spring 81, the other end of which is mounted upon an adjustable slide 82. The slide may be guided in an arcuate slot 83 and may be adjusted, as shown, with respect to a graduated scale 84. Thus where sheets are being handled having a known angular error the slide 82 may be adjusted in angular position so as to center the side guide member 300 in an optimum position to receive the edge of the sheet, with any minor variations in angle from sheet to sheet being accommodated by slight skewing movement of the guide member against the restoring force of the spring 81.

While the operation of the registering arrangement will be apparent from the above description it will be helpful to summarize the operation briefly: Prior to release of a sheet it will be understood that the rod 50 will occupy its left hand position in which the wiper arm 41 is drawn to the left by its spring 61 and in which the bell cranks 46, 52 are rotated clockwise against their respective springs 48, 53 so that the backup roller and side member are upraised relative to the feed board or table. At this time the front guide means 21 is in its active sheet-engaging position. Upon release of a sheet by the means 26, the sheet slides down the feed board until the front edge 16 engages the front guide means 21, 22. The sheet is intentionally released so that the edge 17 of the sheet is slightly inward from the normal position of the side guide member 30, indicated by the dotted lines in FIG. 2.

After the sheet arrives at, and is fully seated upon, the front guide members the rod 50 is drawn to the right. This causes the bell crank 46 to be rotated counterclockwise under the urging of the spring 48 so that the backup roller 44 is in working position. This permits the bell crank 52 to rock counterclockwise under the urging of the spring 53 until the stop 55 is engaged to position the guide member 30 in its edge-receiving position. The wiper arm, swinging in the clockwise direction, applies scuffing force to the undersideof the sheet causing the sheet to be translated in the direction of the side guide member 30. As the edge of the sheet engages the guide member it causes it to swivel through a small angle until the presented face 31 of the guide member is aligned with, and coincides with, the presented portion of the sheet edge, after which no further movement takes place. Assuming the wiper arm 44 is in general alignment with the pivot 33, and that its motion is parallel to the front guide means, the sheet, during translation, will remain in contact with the front guide means, with the 'side guide member 30 moving, of itself, to a final position in which it precisely coincides with the sheet edge regardless of whether the sheet is cut perfectly square. The final position of the sheet is as shown in FIG. 9 in which the sheet simultaneously engages all of the registering guide members 21, 22 and 30. This is to be contrasted with prior art arrangements in which the side guide member is of nonswiveling construction as shown in FIG. 8. In this figure urging of the sheet in the direction of the arrow tends to cause the edge 17d of the sheet to swing into alignment with the face of the fixed side quide indicated at 30d. Asa result a sheet having angular error is moved out of precise seating engagement with the front guide means 21, 22 so that the sheet is no longer in a condition of register as it is taken from the feed board.

' For removal of the sheet from the board the pregripper 25 engages the leading edge and the front guide means 21, 22 is swung downwardly by the synchronizing means 27. The backup roller 44 and the side guide member 30 are raised clear of the sheet. Thus the sheet is free to move in its registered position on the pregripper 25 for transfer to suitable grippers on the impression cylinder 11 where the condition of register is preserved until the sheet is subjected to an impression from the printing cylinder 12.

While light coil springs have been disclosed for the purpose of centering the side guide in a neutral sheetaccepting position, it will be apparent that the invention is not limited to the use of coil springs and that other forms of centering bias, as for example, that produced byv a permanent magnet, may be employed if desired without departing from the invention.

As used herein the term central portion" as applied to the swivel axis of the guide member will be understood to mean a position which is spaced well inwardly from the ends and which is preferably symmetrically related to the ends.

I claim:

l. A sheet registering arrangement for positioning sheets prior to take-off and transfer to a printing unit, comprising a feed board, extensive front guide means located in obstructing transfer alignment at the front edge of the board for registering the leading edge of the sheets, a side guide member located at one side of said feed board for registering the side edge of the sheets, means for feeding sheets one by one onto the feed board along a path which clears the side guide member by a relatively small amount of clearance and into seated engagement with the front guide means, means adjacent the side guide member and synchronized with the arrival of the sheet at the front guide means for urging the sheet laterally into engagement with the side guide member, the side guide member being in the form of a short length of fence presenting a vertical sheet engaging face which extends both upwardly and downwardly a short distance with respect to the surface of the feed board, and means including a vertically extending pivot at the central portion of the guide mem.- her and upon which the guide member is free to swivel so that when the presented edge of a sheet being in angular error is urged laterally into engagement with the side guide member the side guide member is thereby swiveled into self-alignment with such edge with no tendency to dislodge the sheet away from its seated engagement with the front guide means, and means for thereafter gripping the registered sheet and for retracting the front guide means for transfer of the sheet in registered condition to the printing unit.

2. The combination as claimed in claim 1 in which stops are provided for limiting the range of swiveling movement to a few degrees on each side of a neutral position.

3. The combination as claimed in claim 1 in which centering means are provided for lightly biasing the side guide member into a neutral position, the biasing force being sufficiently light so as to be readily overcome by the edge of a sheet being in angular error under the action of the lateral urging means.

4. The combination as claimed in claim 1 in which the centering means is adjustable so as to vary the neutral position in accordance with the angular error which may be characteristic of a given batch of sheets.

5. The combination as claimed in claim 3 in which the centering means includes a light coil spring. 

1. A sheet registering arrangement for positioning sheets prior to take-off and transfer to a printing unit, comprising a feed board, extensive front guide means located in obstructing transfer alignment at the front edge of the board for registering the leading edge of the sheets, a side guide member located at one side of said feed board for registering the side edge of the sheets, means for feeding sheets one by one onto the feed board along a path which clears the side guide member by a relatively small amount of clearance and into seated engagement with the front guide means, means adjacent the side guide member and synchronized with the arrival of the sheet at the front guide means for urging the sheet laterally into engagement with the side guide member, the side guide member being in the form of a short lengtH of fence presenting a vertical sheet engaging face which extends both upwardly and downwardly a short distance with respect to the surface of the feed board, and means including a vertically extending pivot at the central portion of the guide member and upon which the guide member is free to swivel so that when the presented edge of a sheet being in angular error is urged laterally into engagement with the side guide member the side guide member is thereby swiveled into self-alignment with such edge with no tendency to dislodge the sheet away from its seated engagement with the front guide means, and means for thereafter gripping the registered sheet and for retracting the front guide means for transfer of the sheet in registered condition to the printing unit.
 2. The combination as claimed in claim 1 in which stops are provided for limiting the range of swiveling movement to a few degrees on each side of a neutral position.
 3. The combination as claimed in claim 1 in which centering means are provided for lightly biasing the side guide member into a neutral position, the biasing force being sufficiently light so as to be readily overcome by the edge of a sheet being in angular error under the action of the lateral urging means.
 4. The combination as claimed in claim 1 in which the centering means is adjustable so as to vary the neutral position in accordance with the angular error which may be characteristic of a given batch of sheets.
 5. The combination as claimed in claim 3 in which the centering means includes a light coil spring. 